CN-120055898-B - Polishing path planning method for complex curved surface

Abstract

The invention relates to a polishing path planning method for a complex curved surface. Compared with the existing spiral track planning method for complex hole-containing curved surfaces, the method directly generates a bridging-free spiral track to cover the whole three-dimensional hole-containing curved surface, so that the problem that a large amount of bridging is needed for the spiral track among subareas caused by subarea division is avoided, the generated spiral track is shorter, smoother and more consistent in track distance, and the intermittent and severe turning of the track is avoided, so that the movement path of an actuator is smoother, the number of times of path interruption is reduced, and further the processing time consumed by lifting a cutter and turning of the actuator and impact marks on the surface of a workpiece are avoided.

Inventors

• ZHANG XIAOJIAN
• SHEN CHANGQING
• YAN SIJIE
• DING HAN
• ZHANG HAIYANG

Assignees

• 华中科技大学

Dates

Publication Date

20260512

Application Date

20231130

Claims (2)

1. 1. A polishing path planning method for complex curved surfaces is characterized by comprising the following specific steps: Firstly, flattening a hole-containing curved surface to be polished to a 2D plane through parameterization of the curved surface; judging whether a hole exists in the center of a region surrounded by the boundary line of the 2D parameter surface, when the hole does not exist, mapping the 2D region containing the boundary onto a circular disc containing a slit by adopting a conformal slit mapping method, and when the hole exists, mapping the 2D region containing the boundary onto a circular ring containing the slit by adopting annular slit mapping; Step three, generating a spiral track with unequal intervals in a circular domain or a circular domain of the slit mapping, and mapping the spiral track onto the 3D curved surface through inverse mapping of the slit mapping, so as to obtain a spiral processing track of the 3D curved surface; Step four, processing along the curved surface boundary offset line, and removing a small amount of processing residues; The spiral track in the third step is formed by shifting concentric circles with unequal radiuses, the shifting speed of the spiral track and the radius of the concentric circles are adjusted, and the generated unequal-interval spiral line is prevented from intersecting with the slit in the image domain; In the third step, the overlapping area and the uncovered area of the spiral processing track are required to be checked, if the overlapping area is too much, the concentric circle spacing is increased, then the path is regenerated, if the uncovered area is present, the concentric circle spacing is decreased, then the path is regenerated, and the spiral track with moderate spacing can be obtained by the method and used for polishing the 3D curved surface; And step four, when spiral track grinding and polishing is carried out, a small amount of unground areas exist in the areas close to the boundaries of the 3D curved surfaces, and the areas close to the boundaries of track grinding are independently generated or the paths of the ground boundaries and the spiral paths are fused into a whole in an X-shaped bridging or Y-shaped bridging mode.
2. 2. The method for planning a complex curved surface polishing path according to claim 1, wherein the curved surface parameterization in the first step is set to be any one of a Boundary FIRST FLATTENING (abbreviated as BFF) algorithm, a Least square conformal maps (abbreviated as LSCM) algorithm and a discrete Ricci flow-based algorithm.

Description

Polishing path planning method for complex curved surface Technical Field The invention relates to the technical field of polishing, in particular to a polishing path planning method for a complex curved surface. Background The lifting and sharp turning in the grinding and polishing track can cause stress fluctuation in the processing process, and influence the consistency of surface quality, which is particularly remarkable in grinding and polishing weak rigid parts. The spiral track is adopted to polish the complex three-dimensional curved surface of the large-scale component, so that the spiral track has the advantages of less track interruption and smooth steering, and the generation of the spiral track with shorter, smoother and less interruption is important to the improvement of the polishing efficiency and the consistency of the surface quality of the large-scale curved surface construction. However, aiming at a complex curved surface with holes, the traditional spiral track planning method needs to convert a multi-communication area into a single-communication area or divide the multi-communication area into a plurality of sub-areas by adding an additional boundary, and the track needs to avoid the newly added additional boundary, so that the problems of inconsistent track spacing, severe track steering, more track discontinuities, bridging and the like are brought. The problems of large material removal rate change, long processing path, large actuator movement impact, excessive cutter lifting times and the like in the curved surface grinding and polishing process are caused, so that grinding and polishing parameters are difficult to optimize, the grinding and polishing time length is increased, and the consistency of grinding and polishing surface quality, the service life of a cutter and a robot and the precision are reduced. The conventional spiral track generation method mainly comprises a method based on a central axis tree (Medial Axis Tree), a method based on solving an elliptic partial differential equation (PARTIAL DIFFERENTIAL Equations) on a single connected region with disk equivalence or a two connected region with ring equivalence, and a method based on conformal mapping (Conformal Mapping) of single connected disk, square or two connected rings. The method cannot be directly applied to a complex porous curved surface, or the path generated when the method is applied to the complex porous curved surface is uneven, non-smooth and intermittent. Disclosure of Invention The invention provides a polishing path planning method for complex curved surfaces, which aims to solve the problems in the prior art. In order to solve the technical problems, the invention is realized by the following technical scheme that 1. A complex curved surface polishing path planning method comprises the following specific steps: Firstly, flattening a hole-containing curved surface to be polished to a 2D plane through parameterization of the curved surface; judging whether a hole exists in the center of a region surrounded by the boundary line of the 2D parameter surface, when the hole does not exist, mapping the 2D region containing the boundary onto a circular disc containing a slit by adopting a conformal slit mapping method, and when the hole exists, mapping the 2D region containing the boundary onto a circular ring containing the slit by adopting annular slit mapping; Step three, generating a spiral track with unequal intervals in a circular domain or a circular domain of the slit mapping, and mapping the spiral track onto the 3D curved surface through inverse mapping of the slit mapping, so as to obtain a spiral processing track of the 3D curved surface; and fourthly, processing along the curved surface boundary offset line, and removing a small amount of processing residues. Preferably, the surface parameterization in the first step is set to any one of a Boundary FIRST FLATTENING (abbreviated as BFF) algorithm, a Least square conformal maps (abbreviated as LSCM) algorithm, and a discrete Ricci flow-based algorithm. Preferably, the spiral track in the third step is formed by shifting concentric circles with unequal radii, and the speed of shifting the spiral track and the radius of the concentric circles are adjusted to avoid intersecting the generated unequal-pitch spiral line with the slit in the image domain. Preferably, in the third step, the overlapping area and the uncovered area of the spiral processing track are required to be checked, if the overlapping area is too much, the concentric circle pitch is increased, then the path is regenerated, if the uncovered area is present, the concentric circle pitch is decreased, then the path is regenerated, and by the method, the spiral track with moderate pitch can be obtained for polishing the 3D curved surface. Preferably, in the step four, when the spiral track is polished, a small amount of unground areas exist in the area close to the boundary of the 3